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CD STATES PUBLIC HEALTH SERVICE 

RUPERT BLUE, Surgeon General 



BREAD AS A FOOD 

CHANGES IN ITS VITAMINE CONTENT AND NUTRITIVE 

VALUE WITH REFERENCE TO THE 

OCCURRENCE OF PELLAGRA 



BY 

CARL VOEGTLIN 

H 
Professor of Pharmacology 

M. X. SULLIVAN 

Biochemist 
AND 

C. N. MYERS 

Technical Assistant 
United States Public Health Service 



REPRINT No. 333 

FROM THE 

PUBLIC HEALTH REPORTS 

April 14, 1916 

(Pages 936-943) 

[Edition of May, 1918] 




WASHINGTON 
GOVERNMENT PRINTING OFFICE 

1918 



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I 






BREAD AS A FOOD. 



CHANGES IN ITS VITAMINE CONTENT AND NUTRITIVE VALUE WITH REFERENCE TO 

THE OCCURRENCE OF PELLAGRA. 

By Carl Voegtlin, Professor of Pharmacology, M. X. Sullivan, Biochemist, and C. N. Myers, Tech- 
nical Assistant, United States Public Health Service. 

Bread has been from time immemorial the staple article of diet of 
the greater part of the human race. This statement applies particu- 
larly to people living under more or less poor economic circumstances, 
as the cereal foods are comparatively cheap and may be obtained 
easily at all seasons of the year. From the point of view of public 
health it is, therefore, of considerable importance that the bread sup- 
plied for human consumption should possess the highest possible 
nutritive value. The results of the investigations here reported refer 
particularly to conditions prevailing in the United States, and are the 
outcome of some studies on the causes of the occurrence of pellagra 
in this country. Apart from their bearing on the pellagra problem, 
they may be considered of interest from the viewpoint of human 
nutrition. 

From the available data one may conclude that the nutritive 
value of bread made from corn or wheat remained much the same 
from the time of the early settlers until about 1880. During this long 
period bread was prepared from wheat flour or corn meal with salt 
and with or without the addition of other ingredients, such as fresh 
milk, buttermilk, molasses, etc. The wheat flour or corn meal was 
obtained by simply crushing the whole grain between stones, by 
various means, to the desired degree of fineness. The resulting flour 
or corn meal, from which the coarser particles of bran were partly 
sifted out, was then used for making bread. Accordingly the bread 
contained practically all of the nutritive elements of the w T hole grain. 
During the last 50 years, however, radical changes have taken place, 
with the tendency of reducing considerably the nutritive value of 
bread. The factors at work in this change are very closely connected 
with the radical changes in our social and economic life. It may 
suffice to call attention to two of the most important factors: 

The rapid increase in the output of wheat and corn and the 
increase in the cost of labor necessitated the invention of me- 
chanical devices for the more economic milling of these cereals. The 
introduction of the roller-mill system into the United States in 1878 rep- 
resents probably the most important change in this direction. By 

1 Reprint from the Public Health Reports, vol. 31, No. 15, April 14, 1916, pp. 935-943. 
56760°— 18 3 



4 BREAD AS A FOOD. 

means of the roller process it was made possible to separate the various 
parts of the kernel, namely: The germ or embryo, the bran, and the 
endosperm, or starchy part. The latter could then be ground to 
a very fine flour, which, on account of its white appearance, appealed 
to the housewife as an assumably purer product. The germ and 
bran were largely discarded as human foods and put on the market 
as food for cattle, horses, and swine. While it is quite true that 
the highly milled products (wheat flour, corn meal, corn flour, and 
grits) obtained by the roller process are far superior to the old-fash- 
ioned whole-wheat flour and corn meal so far as the keeping qualities 
are concerned, at the same time this modern process deprives the 
finished products of some valuable food constituents. A large 
number of analyses of such products made in the Bureau of Chemis- 
try of the Department of Agriculture and at the Hygienic Laboratory 
clearly show that the highly milled wheat flour and corn meal contain 
less protein, fat, and ash than the old-fashioned products — a fact 
which would be expected, as the endosperm, from which the newer 
products are manufactured, is especially rich in starch cells. 

Other things being equal, the lessened amount of protein, fat, 
and ash in the highly milled as compared with the undermilled prod- 
ucts, while undesirable from the standpoint of nutrition, might be 
considered as a negligible change when compared with the better 
keeping qualities of the newer products, especially in view of the 
fact that in recent years it seems impossible to avoid long-continued 
storage of flour and corn products. The highly milled products, 
however, are often deficient in certain essential accessory food sub- 
stances, which are designated as vitamines. These substances are 
located in the intact kernel in the outer layers (aleurone layer) and 
probably also in the germ. As seen above, the modern roller pro- 
cess eliminates to a great extent the bran and germ, and the re- 
sulting wheat flour, corn flour, and grits (hominy) might be expected 
to be deficient in vitamines, an assumption which has been amply 
verified by Myers and Voegtlin in work, the details of which will 
be published as a bulletin of the Hygienic Laboratory. It may 
suffice here to state that it was found that, whereas the corn meal 
and wheat flour made by the old-fashioned process, which is still in 
use to some extent in the South, contains practically all of the 
vitamines of the whole grain, the highly milled products are con- 
siderably deficient in these substances. 

Fowl, the classical experimental animal for the physiological 
estimation of the vitamine content of foods, will live in perfect 
health for many months on an exclusive diet of wheat, corn, whole- 
wheat flour, or so-called "waterground" corn meal. If these animals 
are fed, however, on highly milled products they will die within a 
month or two of polyneuritis, a disease very similar to beriberi. 



BREAD AS A FOOD. 5 

There seems to exist a perfect analogy between the well-known 
relation of the polishing of rice to its nutritive value, and the mill- 
ing of wheat and corn to the nutritive value of wheat flour and corn 
meal. In the case of beriberi, numerous observations have demon- 
strated the fact that, if the diet of people is largely made up of 
highly polished rice and is otherwise deficient hi vitamines, beriberi 
will make its appearance, whereas, if undermilled rice* is substituted 
for the highly milled variety, the disease is not so likely to break 
out. Little 1 reports an outbreak of beriberi among the fishermen of 
Newfoundland, who lived mainly on bread made from highly milled 
wheat flour. 

From these considerations it would appear that a simple method 
for the determination of the vitamine content of cereal products 
would be of great value. Unfortunately it is still impossible to base 
such a method on the direct isolation of these substances from the 
natural foods. The determination of the total phosphorus content 
of these products, however, seems to give a fairly accurate index of 
the relative amounts of vitamines present. While phosphorus does 
not enter into the vitamine molecule the distribution of phosphorus 
and vitamines within the grain runs practically parallel. Fraser and 
Stanton, on the basis of a large number of observations and analyses, 
came to the conclusion that rice containing less than 0.4 per cent of 
phosphorous pentoxide (P 2 5 ) is deficient in vitamines. Myers and 
Voegtlin have used this method in order to correlate the vitamine 
content of wheat and corn products as found by animal experimen- 
tation with that of the quantitative estimation of the P 2 5 content 
of these same products. Without going into detail, it was found 
that in the case of these cereals the same relation exists between 
P 2 5 and vitamine content as in the case of rice. The following 
table illustrates this point: 



Wheat bread made from highly milled flour 

Whole wheat 

Com grits (highly milled) 

Corn grits (highly milled) 

Corn meal (highly milled) 

Corn meal (old-fashioned rock ground) 

Corn meal (rock ground) 

Corn germ 

Corn, whole 



Per cent of 


Number of days required for ap- 


P 2 5 in 


pearance of polyneuritis in fowl 
fed exclusively on this food. 


dry food. 


0.114 


20-32 days. 


1.120 


No symptoms developed. 


0.169 


23-50 days. 


0.210 


30 days. 


0.30 


35 days. 


0.659 


Remained well. 


0.772 


Remained well. 


2.816 


Remained well. 


0.760 


Remained well. 



While this method does not yield absolute values of the vitamine 
content of cereal products, we propose provisionally the following 
standard for wheat flour, corn meal, and grits (hominy) : For corn 
products the minimum P 2 5 content should not be below 0.50 per cent, 
that of wheat flour not lower than 1 per cent. 



1 Little. Jour. Am. Med. Assa 1912. Vol. 58, 2029. 



6 BREAD AS A FOOD. 

The method of determination of P 2 5 is relatively simple. The 
products are dried at 100° C. and then ashed according to the 
Neumann method. 

We believe that the determination of the P 2 5 index will be found 
of value in all cereal products, except the so-called " Self-raising 
flours." These latter products contain baking powders, which often 
are composed of phosphates. As the label of these flours always 
indicates whether baking powder has been added, it would be an 
easy matter to discard such flours for this purpose. 

We now should like to call attention to another factor involved 
in the reduction of the vitamine content of bread, especially corn 
bread. This concerns the use of baking soda in the preparation 
of bread. Simultaneously with the introduction of highly milled 
corn meal it was found that this product when mixed with salt and 
water did not yield a bread of the same lightness as the old-fashioned 
meal. Housekeepers, therefore, began to resort to artificial leavening. 
Baking soda (sodium bicarbonate) became very popular among them. 
This preparation is used very extensively for this purpose in 
South Carolina, where one of the writers (Voegtlin) had an oppor- 
tunity of studying its uses in cooking. Bread made by means of 
baking soda has under certain conditions a distinctly alkaline taste 
and reaction. In order to prepare bread in this way corn meal is 
mixed with water or milk to which baking soda has been added. 
The resulting mush is baked in the oven. The high temperature 
in the oven liberates carbon dioxide (C0 2 ) from the baking soda 
(sodium bicarbonate) and the latter is transformed into sodium car- 
bonate, a strong alkali. The evolution of C0 2 causes the bread to 
rise. Recent experiments by Sullivan and Voegtlin 1 have clearly 
demonstrated the destructive action of alkalies on vitamines. 2 These 
substances lose their physiological activity when exposed to alka- 
lies, this being especially true at high temperature. Corn bread 
made from old-fashioned (whole) corn meal, sweet milk, and soda, 
when forming the exclusive diet of chickens, leads to symptoms 
of polyneuritis, whereas corn bread prepared from corn meal, sweet 
milk, and salt (NaCl) does not give rise to any symptoms, and fowls 
seem to live in perfect health. 3 Chickens which have developed 
polyneuritis on the corn bread made with sweet milk and soda are 
cured by the administration of vitamines prepared from various 
foods. Hence, we may conclude that corn bread prepared by means 
of baking soda without the addition of buttermilk is deficient in 
certain essential accessory foods (vitamines) and that this deficiency 

1 Proc. Amer. Soc. Biol. Chem. 1916, xvi, p. 24, and unpublished data. 

2 Vedder & Williams, Philipp. Jour. Sci. (B), 1914, vol. 8, p. 175, and Fraser and Stanton, Lancet, 1915, 
vol. 1, p. 1021. 

3 It should be stated that in a large series of experiments with corn bread made without the addition of 
soda one chicken, after several weeks, developed a temporary mild paralysis which was relieved by the 
administration of vitamine. 



BEEAD AS A FOOD. 7 

is due to the destructive action of the alkali (baking soda) on the 
vitamines which were originally contained in these foods. 

The following table illustrates the destructive action of baking 
soda on the vitamine content of corn bread. Ten chickens were fed 
on corn bread of the following composition: 600 gm. of corn meal, 
800 c. c. of sweet milk, and 10 gm. of baking soda. 



Laboratory numbers of animals. 


Number of 
days before 
appearance of 
polyneuritis 
after feeding 
was begun. 


Laboratory numbers of animals. 


Number of 
days before 
appearance of 
polyneuritis 
after feeding 
was begun. 


31 


13 
14 
27 
13 
22 
14 


37 


19 


32 


38 


21 


33 


39 


18 


34 


40 


16 


35 


Average 




36 


17 







Chickens fed on corn bread made with 600 gm. of corn meal, 800 
c. c. of sweet milk, and 10 gm. sodium chloride did not subsequently 
exhibit at any time symptoms of polyneuritis. 

It should be strongly emphasized, however, that the old-fashioned 
way of combining baking soda with sour milk in the preparation of 
bread is a perfectly harmless procedure provided that sufficient sour 
milk is added fully to neutralize the alkalinity of the baking soda. 
The label of the brand of baking soda most in use in this section of 
the South (Spartanburg County, S. C.) clearly states that sour milk 
or tartaric acid should be added in order to obtain the best results. 
The prevalent use in this section of the country of baking soda 
without sour milk or tartaric acid seems to be due to the ignorance on 
the part of the housewives as to the need of an acid, as well as to the 
fact that it is often very difficult to obtain sour milk. 

The writers do not mean to imply that the use of baking soda 
without sour milk will always lead to an injurious action on the 
health of persons eating the bread prepared by this method, although 
such bread is undoubtedly deficient in vitamines. However, when 
the other dietary components, outside of corn bread, are also deficient 
in vitamines the consumption of corn bread made with baking soda 
without the use of sour milk accentuates this dietary deficiency and 
may lead to an impairment of health. 

In conclusion the writers would like to consider very briefly the 
bearing of these findings on the occurrence of pellagra in the South. 
A number of investigators have suggested that pellagra belongs to 
the group of so-called deficiency diseases, meaning that the diet which 
gives rise to pellagra is deficient in certain accessory foods (vitamines) 
having no direct relation to the protein, fat, and carbohydrate con- 
tent of the diet. This hypothesis is based on the observation that the 



8 BREAD AS A FOOD. 

diet of people who develop pellagra seems to be made up of foods 
which are not rich in vitamines. In a general way the dietary stud- 
ies in southern f amilies made by the Experiment Station x of the 
Department of Agriculture, and some more detailed investigations 
by Voegtlin and Miss Nesbit (unpublished) seem to corroborate this 
observation. The last mentioned investigation is being carried 
out in Spartanburg County, S. C, in connection with the work 
of the Pellagra Field Hospital of the United States Public Health 
Service. The diet of the poorer classes of this section of the country 
contains large quantities of highly milled wheat flour, corn meal, fat 
pork, and fresh vegetables and is unquestionably poor in regard to its 
vitamine content. Pellagra has been endemic in Spartanburg 
County for at least seven or eight years. Previous to this time pel- 
lagra very probably occurred, but the disease was not so prevalent 
as at present. It is obvious that a satisfactory solution of the cause 
of this increase in pellagra incidence is intimately connected with the 
etiology of this disease. It is important that a satisfactory answer 
should be found as to how the dietary conditions of the population 
of the South changed previously to the great increase in pellagra. 

We believe that this problem is quite complex, inasmuch as several 
factors must be taken into consideration. These are: (1) Changes 
in the economic conditions of the population; (2) changes in food pro- 
duction and food supply; (3) changes in the method of cooking food. 

In regard to the influences of changes in the economic conditions 
of people on the composition of their diet it might be expected that a 
considerable decrease in the earning capacity of the poorer people, 
or an increase in the cost of foods, would be followed by changes in 
their diet. Everyday experience teaches that under such conditions 
the more expensive foods (meat, eggs, and milk) are reduced in the 
diet. People, as a whole, consume fewer eggs in the winter season 
when the supply of eggs is reduced and their cost correspondingly 
increased. Yet it seems that just these more expensive foods, such 
as milk, eggs, and meat, are efficient in the prevention and treatment 
of pellagra. These same foods are also rich in vitamines. A reduc- 
tion of milk, eggs, and meat in the diet would, therefore, reduce 
its vitamine content, unless other dietary components rich in 
vitamines (legumes) were increased proportionately in the diet. An 
interesting example of the intimate relation between the appearance 
and disappearance of pellagra and changes in the economic conditions 
is found in the history of pellagra in France, referred to in a previous 
article. 2 Pellagra made its appearance in southwestern France (1820) 
soon after the reign of Napoleon, a period which was followed by 
extreme poverty. The available accounts characterize the diet of 

i Bulletins No. 38, No. 71, and No. 221. 

2 Jour. Am. Med. Assn., 1914, LXUI, p. 1095. 



BREAD AS A FOOD. 9 

the people at that time as extremely monotonous, being largely com- 
posed of cereals, fat pork, and a few fresh vegetables. With the 
improvement of the economic conditions beginning with 1860 pellagra 
began to disappear, simultaneously, it seems, with an improvement 
in the diet of the people, which now includes more meat, milk, and 
eggs. At the present time pellagra is practically unknown in France. 
A better illustration of the intimate relation between economic condi- 
tions, diet, and pellagra could hardly be found. 

Sydenstricker, 1 in a recent statistical study, calls attention to the 
relation of pellagra to the lise in the cost of foods in the United States. 
He points out that as a result of the economic depression beginning 
with the year 1907 the cost of food has increased out of proportion 
to the increase in wages, and that the pellagra incidence has also 
increased considerably since 1907. Simultaneously there took place 
a reduction in the diet of the people of such animal foods as milk, 
eggs, and meat. We fully agree with this author that the above- 
described relations between pellagra and increase in the cost of food 
may explain, at least partly, the more or less rapid increase in pel- 
lagra during the last decade. The resulting reduction in the diet of 
foods relatively rich in vitamines (milk, eggs, and meat) might, there- 
fore, have led to a dietary deficiency. 

The writers believe, however, that other factors as above indicated 
may also play a rdle. It is interesting to note that beginning with 
the year 1878 the introduction of highly milled corn and wheat 
products began. These highly milled products began to replace the 
old-fashioned undermilled cereal products. This change took place 
gradually and is not completed at the present time, as there are still 
a good many old-fashioned mills in the South. On the whole the 
South, due largely to the increase of cotton farming and a decrease 
of the raising of corn and wheat became more and more dependent 
on the North for its supply of cornmeal, grits, and wheat flour. It 
was found that practically all of these cereal products consumed in 
cotton-mill villages in Spartanburg County and in Spartanburg city 
were highly milled products imported from Northern States or 
manufactured by southern mills using modern methods of milling. 
By means of the P 2 5 index this was easily demonstrated. Feeding 
experiments of these products and others obtained from various 
sections of the South also showed them to be deficient in vitamines. 

It should be emphasized, however, that the authors met with cases 
of pellagra in farmers who lived on old-fashioned corn meal, ground in 
old-fashioned mills from home raised corn. Very often these persons 
stated that they bought their wheat flour at stores which sold only 
highly milled imported products. It is impossible to get accurate 
statistics on the substitution of highly milled cereals for the under- 

» Sydenstricker, Public Health Rep., 1915, Oct. 22. 



10 BREAD AS A FOOD. 

milled products of former days, but from statements of wholesale 
dealers supplying this section of the country (Spartanburg County, 
S. C), it would appear that during the last 15 or 20 years there 
has been a gradual increase in the highly milled products. This 
same period has also seen the great increase in the pellagra inci- 
dence. 

Concerning the use of baking soda in the preparation of bread, it 
was found from inquiries made among housekeepers that the use 
of baking soda became very common some 20 years ago, simul- 
taneously with the introduction of highly milled corn meal. It is 
difficult to ascertain how rapidly the use of baking soda in cooking 
was taken up by the people. The writers' experience in the cotton- 
mill villages of Spartanburg County has demonstrated that most of the 
families use this preparation at the present time, not only for baking 
bread, but even in the cooking of beans and other foods. This last- 
mentioned use of baking soda is the result of carelessness in cooking 
on the part of housewives in cotton-mill villages. Very often the 
person who attends to the cooking is also working in the mill, and has 
very little available time for the preparation of food for the family. 
Under these conditions the baking soda is added to beans and other 
foods in order to shorten the time of cooking, as the baking soda, 
when added to the water in which the beans are cooked, will cause 
the rapid softening of this food. There can be little doubt as to the 
greater or less destructive action of the soda on the vitamines of the 
beans under these conditions, although no direct experiments have 
been made on this point. 

We see, therefore, that several factors seem to have played a r61e 
in the reduction of the vitamine content of the diet of the people of 
Spartanburg County during the last 20 years. Most prominent 
among these influences are: First, the reduction in the diet of vita- 
mine-rich foods (fresh milk, eggs, and meats) ; second, the introduc- 
tion of highly milled cereals; and, third, the use of baking soda, which 
was shown to have a destructive action on the vitamine content of 
bread. From the most careful and detailed investigation of the 
dietary conditions of certain communities in Spartanburg County it 
is evident that a large proportion of the people, especially in mill 
villages, live on a diet which is deficient from the point of view of its 
vitamine content. Wheat biscuits made from highly milled wheat 
flour and corn bread made with baking soda without the addition 
of buttermilk are the staple articles of diet among the people, and we 
have found families in which these foods represented about three- 
fourths of the entire diet. The fact that the above-mentioned influ- 
ences, which have undoubtedly reduced the vitamine content of the 
diet, made themselves felt a relatively short time before the rapid 
increase in the pellagra incidence in this section of the country, fur- 



BREAD AS A FOOD. 



11 



rushes considerable evidence in favor of the vitamine-deficiency theory 
of pellagra. It will be left for future investigations to prove or dis- 
prove the correctness of this assumption for other pellagrous sections 
of the South. The reported results emphasize the fact that, in study- 
ing the etiology of any disease which is assumed to be of dietary 
origin, it is essential to pay careful attention to what might appear 
on superficial examination as trivial details. 

From the broad view of nutrition, it is very probably immaterial 
what kind of flour is used in making bread provided that an adequate 
mixed diet is consumed which will supply sufficient of the essential 
dietary components outside of the cereals contained in the diet It 
may be added that the great majority of the people in this country 
live on a well-balanced, sufficient, mixed diet. 

o 



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